轴突导向分子Netrin-G1抗痫机制研究

Netrin G1 is a member of axon guidance molecules involved in synaptic plasticity ,which can direct migration of axon and cell .Studies have shown that genetic polymorphism of netrin G1 is associated with a number of disorders characterized by altered synaptic plasticity such as schizophrenia and Strokes. Thus,as a kind of synaptic plasticity-related diseases, we speculate that genetic polymorphism of netrin G1 is associated with the susceptibility of epilepsy. Previous studies have shown that after the gene silencing and over expression of netrinG1,the KATP channel subunits Kir6.1 and Kir6.2 down-regulated,which indicated netrinG1 may exert an antiepileptic effect through regulation of the KATP channels. In this study,we aim to speculate that netrinG1 may play an antiepileptic role by regulating the KATP channels via the following ways such as molecular biology, morphology, ethology, electroencephalogram and electrophysiological methods.However,whether netrinG1 has an antiepileptic effect and the exact antiepileptic mechanism of netrinG1 is still unknown.Therefore,further exploration of the antiepileptic mechanism of netrinG1 will help to explain the pathogenesis of epilepsy,which will also provide new targets for antiepileptic treatment.

Netrin-G1作为一种与突触可塑性相关的轴突导向分子，参与轴突生长和细胞迁移，研究发现Netrin-G1基因多态性与多种突触可塑性相关性疾病如精神分裂症、脑梗塞等的易感性相关。而癫痫作为突触可塑性相关性疾病之一，我们推测Netrin-G1基因多态性与癫痫易感性相关。前期实验结果发现Netrin-G1基因沉默和过表达后，KATP通道亚基Kir6.1、Kir6.2 mRNA和蛋白表达下调，因而Netrin-G1可能通过调节KATP通道激活发挥抗痫作用.本研究通过体内体外水平采用分子生物学、形态学、行为学、脑电图、电生理等多种实验方法从不同层面论证Netrin-G1通过调节KATP通道激活发挥抗痫作用。Netrin-G1是否发挥抗痫作用以及其具体抗痫作用机制尚不完全清楚。因而研究Netrin-G1具体抗痫作用机制将有助于阐明癫痫的发病机制，同时也为临床抗癫痫治疗提供全新的靶点。

癫痫是一组以大脑神经元细胞异常放电为主要特征，由诸多原因所致的，短暂性、反复发作性的中枢神经功能失常综合征。轴突导向分子Netrin-G1具有轴突诱向和细胞迁移诱导作用，可能通过引起突触重组及轴突芽生引起异常神经网络的形成促进癫痫的形成，而已有多项研究发现Netrin-G1基因多态性与多种突触可塑性相关性疾病如精神分裂症、脑梗塞等易感性相关。有研究发现miR-135b可能是Netrin-G1的上游信号分子。而KATP通道是一种能够将细胞电活动与代谢相藕联的非电压依赖性钾离子通道。诸多研究发现，KATP通道能通过改变细胞内的ATP/ADP水平而发挥抗痫作用。本课题小组通过在体内实验发现2-DG通过上调KATP通道亚基Kir6.1、Kir6.2 mRNA和蛋白表达而发挥抗痫作用。本项目以miR-135b以及Netrin-G1和KATP通道切入点，研究2-DG是否介导miR-135b-netrinG1-KATP信号通路发挥抗痫作用。. 本项目在体内与体外两个层面上，应用行为学，脑电图，RT-PCR，western-blot方法检查痫性动物模型上netrinG1，KATP的表达变化，应用膜片钳技术检测致痫脑片上神经元膜电位变化，比较使用netrinG1抑制剂以及miR-135b抑制剂和2-DG干预条件下同，上述各参数的变化。研究发现糖酵解抑制剂抑制剂2-DG介导miR-135b-netrinG1-KATP信号通路发挥抗痫作用。这些发现深化了miR-135b-netrinG1-KATP信号通路与癫痫发病机制的认识，为进一步探讨应用糖酵解抑制剂2-DG在抗癫痫治疗中应用提供科学依据。